The proposed study has two major goals. First, we will determine the extent to which the nation's outpatient drug abuse treatment units are using treatment practices and providing services that meet empirically-established standards of care in several key areas. These areas include: treatment duration and intensity; clients' use of primary health care, mental health care, and social services; HIV and Hepatitis prevention efforts; availability of special services for women and ethnic minorities; methadone dose levels; and access to treatment. We will examine both variation and changes in these treatment practices and services. Second, we will identify organizational factors (e.g., units' managed care arrangements, ownership, staffing) associated with variation and change in treatment units' practices. These factors include unit: ownership; accreditation; funding sources and mechanisms--especially managed care; location (both geographic location and location in a parent organization such as a hospital); community demographic characteristics and health care resources; referral sources; treatment goals/philosophy; staff and client characteristics. To achieve these goals, we will continue the National Drug Abuse Treatment System Survey (NDATSS) in 2003. The 2003 data will give us a current picture of key practices and services in treatment units across the nation (n=600 treatment units). Further, with the addition of the 2003 survey, we will have data from a representative sample of outpatient non-methadone and methadone units for 1988, 1990, 1995, 1999/2000 and 2003. More than half of the treatment units to be included in the 2003 sample (n=324) have already participated in NDATSS in 1988, 1990, 1995, and 2000; and, 489 units participated in our study in both 1995 and 2000. Thus, we will be in a strong position to monitor changes in practices over 15 years (1988-2003), and to make causal inferences about determinants of these changes to inform both policy and practice. In short, NDATSS is well-positioned to become the critical source of information for monitoring and analyzing the on-going evolution of the nation's outpatient drug abuse treatment system.